Opened Inkscape today and tried to do some work but running into problems and not sure how to fix. Draw a simple rectangle and try to fill and it doesn't fill. If I then click on the rectangle it disappears. Stroke works but not fill. Also if I select the elipse shape it draws a rectangle. The last job I did was a square, bezier line corner to corner, no fill and the bezier line I used stroke 8px and dashed line. Now I can't fill anything......can someone tell me what settings I need to amend. I'm using version 48.4. Many thanks....I'm stuck!

Probably you set a totally transparent fill for the rectangle
-make sure the opacity is set to 100% and not 0%, and that the fill has an alpha value of 255 at the fill and stroke panel (Shift+Ctrl+F).
If you want to see the "disappeared" rectangles, switch the display mode to "outlines only".

With the ellipse tool I'm guessing a small angle was given, and what you see is the (dashed) stroke on a small arch.
After you set a right fill, and preferably no stroke, click on the ellipse tool controls and set the angle from 0° to 360°.

Also, there's a color palette running along the bottom of the app. Select an object and clicking on a color, sets the fill for the object. Shift+click sets the stroke color. Right click pops up a small menu to set the fill or stroke. Way over on the very right of the color palette is a small arrow pointing left. Click on it will bring up a menu to set different palettes.